Further evidence that, never mind what Tony Blair might have you believe, the British are very different from the Americans was provided in a conversation I had with Gabriella Ranelli de Aguirre during a coff ee break at San Sebastián's sixth international gastronomy congress.

Gabriella, despite the name, is herself American. But she is married to a Basque, lives in San Sebastián and earns her bacon running what she calls 'culinary and cultural tours' in northern Spain. Sounds like hell, but she seems to make a decent living out of it.

Most of her customers are either American or British. 'The Americans are serious, hard-working tourists,' Gabriella observed. 'The Brits are more fun-loving.' Was she by any chance referring to the islanders' distinctly un-American national pastime of getting sloshed? 'Of course!' she said, smiling the complicit smile of the converted fun-lover. 'But that's not the whole story. The Brits have less need to go to the big-name restaurants than the Americans do. They enjoy going out for tapas just as much - maybe more.'

Count me in with the fun-loving Brits. It's not that I distrust haute cuisine. It's just that in San Sebastián the quality of everyday grub is so remarkably, spectacularly haute already that it seems a waste to spend the night dining solemnly at a Michelin three-star when you can nosh it away in the city's magnificent tapas bars. The reason I was in San Sebastián in the first place was to see some of the world's most celebrated chefs performing at the gastronomy congress; the biggest event of its kind anywhere, I was reliably told. There's a reason why they hold it here. Spain is the 'in' place for the culinary elite these days, and San Sebastián is the best place to eat in Spain. The congress did justice to the city. The grand masters - Alain Ducasse, Ferran Adriá - put on a terrific show. Watching the extraordinary Adriá in action, freezefrying eggs in liquid nitrogen, was a mouthopening experience. But if the plan was to close your mouth around an item of food, then to savour and swallow, you were better off abandoning the centre where the congress was being held and diving into the nearest bar. Any bar.

On a previous visit to the city Spaniards consider not only the most elegant in the Basque country, but in the whole of Spain, I had formed the opinion that you could spend your entire life trying - and failing - to find a place where they would serve you a less than delicious piece of food.

Within minutes of arriving in San Sebastián, I put my theory to the test by walking early in the afternoon into the first bar that caught my eye. There was nothing remarkable about it to the eye. It was called Bideluze. It was what passes in San Sebastián for a local pub . And it was outstanding. The bar itself, la barra they call it, was creaking under the weight of plate after plate of delicious morsels, most of them astride a slice of txapata or baguette. They don't call them tapas here, though they know exactly what you mean if that is what you do call them. They call them pinchos. The Basque custom, observed in every single bar in the region, is to lay out assorted pinchos on the barra. What you do is ask the barman (it is not often a barwoman) for a plate, and simply load onto it the things you wish to eat. It is up to you to keep tabs of how many pinchos you've eaten; when the time comes to add up the tally and pay up, the barman will trust you not to have cheated.

Apart from the standard red pimientos stuffed with bacalao paste that Bideluze offered, apart from the plump, green Gernika peppers, the garlic-speckled anchovies in oil and vinegar, the chorizos, the cheeses and chicken croquettes, the bar also had quails' eggs and bacon, and a little dish known locally as mejillones tigres - tiger mussels. These are served hot on a large, flat seashell and covered with a thin crust of egg-fried breadcrumbs under which nestles a tangy little concoction of finely chopped mussels swimming in a creamy blend of olive oil, chile and bechamel sauce. As I scooped the shell's contents out and drank the fizzy rosé the locals seemed to consider the tigres' correct accompaniment (there was also Guinness and Murphy's Irish Red on tap), I saw a barman glide past. The plate he was bearing was dripping with the most wondrously marbled, acorn-oil-drenched slices of Jabugo ham - more evidence for the eyes of what was abundantly clear, that everything we were eating here was the freshest, finest quality produce. The proud locals would not have it any other way. Basques are exquisitely fussy about their food, especially the natives of San Sebastián. 'Try setting up an eating establishment that does not serve the freshest food, bought that morning in the market,' a friend there told me, 'and you'll be out of business in a week.'

It is striking, this fineness of sensibility - the almost Japanese delicacy - the Basques have with their food. Because it is so at odds with the national character: they're a brusque lot, headstrong, easily angered. You can see where the fanatical nationalism comes from, the sheer madness - never mind the ETA terrorists - of that 50 per cent or so of the population whose voting patterns indicate they would like to secede from Spain.

Like many Catalans, only more so, this breed of Basque insist on seeing themselves as victims, on feeling aggrieved at the unfair treatment they receive from what they call 'the Spanish state'. And yet there is quite possibly no other group of people in Europe that enjoys a better quality of life. Such thoughts passed through my mind on a stroll along the arching promenade that lines San Sebastián's Concha, the city's beautiful beach, in the direction of my next pincho stop, Casa Gandarias, in the old heart of the city. I had not found the Gandarias in any tourist guide. Nor had it been recommended by any of the half dozen or so locals I was to consult during my stay in the city. (In fact, the locals seemed distinctly underwhelmed when I told them later that I had eaten there.)

The idea had come from a couple of friends of mine in Teddington, Surrey. Either the Teddington couple and I were pitifully easy to please, or the local experts were the most impossible snobs. I want to believe it is the latter. Because the truth is that during the hour and a half I spent at Gandarias I was in food heaven. It was 2.30 in the afternoon and the clientele were spilling out onto the street, it was so busy. I elbowed my way through to the barra, heaving under the weight of a tapas spread four times more abundantly than the one at Bideluze. The dishes that were not on display, because they needed to be cooked on the spot, were listed on a blackboard.

By astounding good fortune I found myself an empty stool at the barra, summoned the nearest barman - big, bald, as gruff as it gets - and asked him if it was actually true, as another blackboard before me indicated, that Belondrade y Lurton white wine was available, 'by the glass'. 'That's right,' the barman replied, looking me menacingly in the eye, as if a bell were about to ring in the first round of a prize fight. 'Belondrade y Lurton, the finest white wine in Spain ...by the glass?' I repeated. 'That's correct,' my antagonist said, betraying, I thought, the faintest germ of pride; and maybe even a suggestion of surprise at this non-Basque barbarian's appreciation of the quality of beverage on display.

In either case, it was staggering to come across such a find in such a place, and a most eloquent expression of what is so special about eating out in San Sebastián. The most ordinary, everyday, humdrum of establishments serve food and drink of the standard you would expect to find in a restaurant run by the most lubricious maitre d', the most pompous sommelier. So I ordered a glass of Belondrade - made by a French couple in Rueda, an hour and a half north of Madrid, from the ancient Verdejo grape - and then some crab and octopus and prawns and some sizzling kidneys and a lamb brochette and black pudding (morcilla) with red peppers and the best, moistest potato omelette I've ever tasted and a few more slices of that glistening ham. You have to order ham in Spanish tapas joints if you want to be taken seriously.

Ham - of endless quality and variety - is the great national unifier. It is what gives lie to the delusion the Basques - and the Catalans and some Galicians - have that they are culturally different from their Iberian neighbours. (The Portuguese are different, of course, because, among other reasons, for them it is cod, not ham, that is king.) There were also some quite spectacular pieces of dark red meat on show, available either in the form of a fat slab of steak or in choice little cuts delivered on a slice of crusty bread. My friend from Teddington had memorably feasted on a fat one. The best piece of meat he'd ever had, he said. But he was still digesting it three months later so I plumped for just the one little pincho, garnished to simple perfection with thick chunks of rock salt. The piece de resistance, though, was the foie, also in pincho form. Rinsed down with that liquid Belondrade bouquet, it was an Elysean excess.

But Belondrade wasn't all that was on offer - there were plenty of other terrific wines, too. There was also a range of Scotch whisky that beggared belief. The labels on the bottles were a Who's Who of single malt's finest: Ardbeg, Bladnoch, Caol Ila, Laphroaig, Inverleven, and more - further proof, if at this stage it were needed, that I had penetrated a superior civilisation. I stuck to another glass of my favourite Spanish white for my cheesecake dessert, delivered on a raspberry-lined, toothpaste-white oval plate. And that's another thing. Each dish had its own plate: round, square, triangular or oval, depending, as far as I could surmise , on whether it was fish, meat or fowl.

I rounded the meal off with a cortado coffee, which is an espresso cut with hot milk. I have had thousands of cortados but this one tasted better than any other . The rough enchantment of the place had got to me. During the whole 90 minutes I spent at Gandarias, I never ceased to be amazed and entranced by the fact that I was eating and drinking in a place as regular to San Sebastiánites as the local King's Arms is to the inhabitants of Stockton-on-Tees. Oh, and it all came to €30, including tip.

'The secret,' Gabriella Ranelli reflected, 'is that they approach their food with so much mimo.' Mimo is what you do with babies you love. It means a combination of things, both abstract and physical. It means to cherish, but also to pamper, typically while making a tender cooing sound. 'That's how the Basques relate to food,' Gabriella continued. 'In the restaurants and bars it's not just about making money. It's about pleasing - and not just your clients, but yourself.' That is why even the wine glasses at Gandarias were of the finest quality. It isn't about money but about doing justice to a culture. There is a phenomenon in the Basque country known as 'la sociedad gastronómica' . It's a kind of club, usually based around a group of male friends who inhabit the same neighbourhood, in which people gather to discuss and cook food. The gastronomic society will have its own fully equipped kitchen and members will take turns to cook for each other.

Where, in other latitudes, people play golf or tennis or bridge, the Basque sport is cooking. An Andalucían friend who recently moved from Madrid to San Sebastián said he was surprised to discover a state-of-the art kitchen on the ground fl oor for the use of residents in the block of fl ats where he was living . 'In the block where I lived in Madrid we had a pool and a tennis court,' he said. 'Here - and it's the same in these kinds of places all over the Basque country - we have this great big communal kitchen.'

The measure of how fanatical these gastronomic society people must be about their food was provided by a Basque friend José Luis, who does not belong to one. In fact, he told me, he's not very good at cooking at all. José Luis is in his forties and has a group of a dozen or so mates he has been hanging out with all his life. They have a number of rituals, the most solemn of which is that on your birthday you must cook a great big extravagant meal for everybody else. 'So you cook one, too?' I said. 'Of course,' he replied. 'But I thought you said you couldn't cook.' 'Well, I need a couple of days to prepare the meal, and I follow practically every step from a recipe book.' 'And you do this for a dozen people and you say that's not cooking?' 'No, of course not. Cooking is when I put three or four fresh ingredients in front of you and in an hour you've made a great dish out of them.' So there you are. As far as Basques who are not too fussed about their food are concerned, using a recipe book is cheating. The gastronomic societies have existed forever.

Perhaps the historical reason why they should have emerged in this part of the world in the first place has to do with the natural abundance of food. There is the sea (the Basques are fi shing folk by ancient tradition) and there is excellent agricultural land. Most of Spain is dry and brown but the Basque country is lush and green, with big valleys and gentle slopes that suggest the Swiss lowlands, but with more heat and sun. 'There are still lots of small farms and San Sebastián has more Michelin stars per head than any place on earth the quality of the produce really is fabulous,' said Gabriella, who has lived in the Basque country for 15 years and knows a fresh Gernika pepper when she sees one.

Talking of which, a visit to the main market in San Sebastián is the city's second obligatory tourist destination after la Concha beach. The fish counters are a pleasure to behold, but what will stay with me is the fragrant smell of the lettuce. Another reason why the food is so good has to do with the emergence 25 years ago of what is known as 'new Basque cuisine'. Its champion is local legend Juan Mari Arzak, who runs a three-star Michelin restaurant by the same name. Since then the sky's been the limit. As Gabriella says, 'In San Sebastián you have it all, the entire range - from the most avant-garde dishes you'll fi nd anywhere, to the best set-price lunches, to the best tapas; everything!' Ask the inhabitants of southwest France: they flock to San Sebastián, which they consider their food mecca. Actually, it is, in all likelihood, the best place to eat in the entire Western world. If you doubt it, consider this: San Sebastián, which has the same population as Stockton-on-Tees, has more Michelin stars per inhabitant than any place on earth. Fifteen, to be precise. 180,000 people live in San Sebastián, Spain's 27th largest city but the one with the highest property prices. That means one star for every 12,000 inhabitants. (London, with a population 200 times larger, has 34 stars.)

'What the top restaurants do is raise the level of the ordinary eating place,' Gabriella said. 'But the great chefs take much of their inspiration in turn from the everyday places. One feeds the other, so to speak, and the public, who get accustomed to better and better food, become more and more demanding.'

One of the reasons why the gastronomy congress was held in San Sebastián is that it is the one place in Spain where the public can be relied upon to turn up in large numbers. These are people who save up all year to eat at Arzak or one of the other mega-star restaurants like Martin Berasategui, Akelare or Zuberoa, in the same way that people elsewhere save up for a holiday in Miami. So offering them a gathering of the cream of the world's chefs is like the Beatles coming to town.

The congress venue was a big, boxshaped convention centre by the sea known as the Kursaal, the kernel of which is a large amphitheatre used by symphony orchestras. It was standing room only in the amphitheatre when Ferran Adriá (who is to San Sebastián as David Beckham still is to Tokyo) did the first of his star turns. There were about 30 chefs in all - from France, Italy and the United States as well as Spain - who did half-hour presentations on stage of some of their favourite dishes, complete with live video connections to kitchens where their staff did the chopping and mixing. This was decidedly not for the housewife back home to imitate. It was - especially in the case of the show-offy Spaniards - the culinary equivalent of going to a wayout-there haute couture fashion show. In the case of Adriá, it was like his restaurant, el Bulli. It was beyond food, beyond eating. That was what I had been doing at Bideluze and Gandarias. This was pure spectacle. Virtuoso for virtuoso's sake. There was an elaborate machine that made mint juice, long syringes, odd Styrofoam contraptions, deep pots belching white smoke (this was the liquid nitrogen).

The ingredients were eggs, asparagus, olive juice (green as pea soup), vinegar dust and raw powdered calcium. The point was to cook not by applying heat to the raw materials, but extreme cold. The end result was a sort of poached egg encased in a transparent asparagus gelatine. You cut through it and the yolk ran liquid as a fried egg's. It was a staggering spectator sport, as was the act of creation by which another playful Catalan, Joan Roca, made a brittle, see-through, balloon-sized orb densely packed with cep smoke. To 'eat' it, you crack the balloon and inhale. In between all this there was some delightfully simple stuff , like warm oysters with green apple juice. One of the French chefs (I think he was taking the mick) offered as his contribution a big fat roast chicken. An Italian made snails. An American chef cooked bread. The most notable difference between the Spaniards and the rest was that the Spaniards worked with the cool precision of laboratory scientists, or heart surgeons. In the case of Andoni Aduriz (the most avant of the avant-garde Gabriella was talking about) the analogy is not extreme. Every one at the congress I spoke to mentioned his name in hushed tones.

Thirty years old, Andoni - as everyone calls him, the same way Brazilians call their football superstars by their first names - is the boy wonder of global cuisine. (Well, actually, if you ask Ferran Adriá, the most interesting contemporary genius is Britain's very own Heston Blumenthal, but that's another story.) His special gift, I was told, is making foie. So obsessive is Andoni, who looks like Harry Potter, about this particular art that he frequented Spain's leading liver research hospital in Granada for a period of two years in order fully to grasp the ins and outs, the precise fat-protein ratio, the exact enzyme composition of the said organ.

As a consequence he understands foie and can cook it better than anyone alive, gauging the different temperatures required at every forensically delicate stage of the coction process to a thousandth of a degree. I went to his restaurant, Mugaritz, in San Sebastián's mountainous southern outskirts, for dinner. I had the dégustation menu, each of a dozen dishes more minimalist than the next, and nothing to do with everything else that's going on in Spanish cooking. The Adriá school is exuberantly Dalíesque. Andoni is Zen austere. The first off ering, consumed in one gulp at the end of a very long spoon, was a sea anemone, a gooey grey thing whose naturally kidneyish, urine tang was helpfully off set by a hint of lemon.

Next up, raw thistle leaves with milk skin, garlic dressing and an olive infusion. Then herb salad and laminated mushroom followed by hay consomme and a morsel of sea urchin leavened with garlic and walnuts. A tasty little chunk of Iberian pig went down nicely after that, as did the scallop of foie, first roasted, then chargrilled and accompanied by a consomme of date pips . And so it went on. A Spanish food critic sharing the table with me noted that I was consuming rather more bread than one might ordinarily expect to eat at a top-of-the-range Michelin establishment, but the truth was that for most of the meal I was bloody hungry.

'He takes risks, Andoni,' my dinner companion observed. 'He lives on a knife edge.' But, I asked, did he like Andoni's food? 'Look,' the Spanish gourmand replied, 'you either go along with this spiritual game of his or, frankly, you find him a pain in the balls.' A bunch of Catalan chefs at the table next to me who'd come along to San Sebastián to pick up some tricks at the gastronomy congress really got it badly in the balls. There were five of them, all good-quality chefs in their own right who serve straightforward fine food in a town on the foothills of the Pyrenees. After dinner I drove back with them to the city centre. They were indignant. Enraged. I couldn't print most of what they said but it boiled down to this: 'What a load of pretentious rubbish!' I said I tended to agree, while humbly acknowledging that if the cream of Spanish cheffery believed this guy to be the Picasso of his day, well, cubism was derided too when it first appeared on the art scene.

What was true, and where I entirely agreed with my outraged Catalan crew, was that I badly felt a need for one of those fat crimson super-steaks my friend from Teddington had gorged on. The next day my friend José Luis, the Basque who doesn't care about food, had us walk the streets for an hour before we found just the right place to have lunch. Asador Trapos, which dishes up traditional pre-nouvelle cuisine Basque food, was just what the doctor ordered. José Luis and I shared a plate of thick green beans with garlic and another of artichokes with clams, and then I had my longed-for half-kilo slab of red meat.

Chuletón de buey is what you ask for, the literal translation of which is 'ox chop', but what it really means is beef steak. I loved the fact that the waiter did not even ask me how I'd like the meat done. He brought it blood rare, sprinkled with rock salt, and accompanied by a bottle of red honest-to-goodness Rioja. I kept going back to the congress, gawping at the cutting-edgery of it all, but it was Asador Trapos and the tapas bars I went to that will linger much longer in the mind. Take a place called Barandiarán that I popped into one morning for breakfast. Again, I had never heard of this place before walking in, again it was a regular everyday place with soiled napkins on the floor but the spectacle that awaited me at the barra was a feast for the eyes.

This being breakfast, they had held back on the kidneys and foie wasn't on the menu. Instead, among the self-service goodies on display were succulent pieces of cinnamon-coated French toast, smoked salmon, crabmeat and shrimp on toast and, of course, potato and onion omelette. The only juice available was orange, freshly squeezed, and the cortado coff ee was of a quality, as they say in Spain, to revive the dead. A tapas bar that the locals did recommend was Bar la Cepa, just down the road from Gandarias in the old quarter of San Sebastián, which is where most of the best pinchos in town are to be found. As far as I could tell, it was Casa Gandarias all over again, though (and the local experts will have to forgive me) not quite as fine.

The best recommendation was that four pinchos into my meal, Ferran Adriá walked in with his wife. It is the second time this has happened to me in a year, the first having been at a very hip tapas place indeed in Adriá's native Barcelona. I was struck by the fact that, on arrival, he ordered, as he had done the first time around, a large plate of ham. It is his antidote, you can't help feeling, to the elaborate intricacies with which he concerns himself in his day job. So, I asked Adriá, was San Sebastián the best place to eat in the world? My expectation was that he would cry 'yes', or make some sly remark along the lines that it was almost the best, after Barcelona. Yet there was not a tinge of patriotic prejudice in his reply. Quick as a flash he said, 'No. Shanghai is better. Maybe Thailand, too.' Shanghai? 'The variety and inventiveness is amazing.' And Thailand? 'The freshness of the produce is remarkable .' So was San Sebastián the best in Spain at least? 'Of course! What do you mean?' he replied. 'It's the best in Europe. The best in the West. No doubt about that at all. And if you push me, in terms of the average quality of the food, in terms of what you can get at any place you happen to walk into, maybe it is - probably it is, yes - the best in the world.'